Histiocytic sarcoma involving the small bowel and regional lymph nodes. The patient was a middle-aged male who presented with fever, weight loss, and abdominal pain. He was found to have a 10 cm mass involving the intestines with enlarged regional lymph nodes. The tumor cells were positive for CD68, CD4, CD31, and S100. Image courtesy of: Karen Pinto, DNB, FRCPath, Kuwait; Used with permission.